Find how deep to bury a fence post and its concrete.
A post should be buried below the frost line and at least a third of its exposed height. The concrete volume is the filled hole volume holding that buried portion. Burying below the frost line prevents frost heave, and the third-of-height rule keeps the post stable under wind load.
Fence Post Depth
Buried depth = max(frost line, post height / 3)
Buried depth = max(frost line, post height / 3) A post should be buried below the frost line and at least a third of its exposed height. The concrete volume is the filled hole volume holding that buried portion.
Burying below the frost line prevents frost heave, and the third-of-height rule keeps the post stable under wind load.
This calculator takes 3 inputs: Post above ground, Frost line, Hole diameter. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.